Objective: The present study has investigated the influence of testicular or peritoneal macrophages with or without stimulated by a bacterial lipopolysaccharide (LPS) on Leydig cells in vitro by using the methods of cell culture, cell hemotixylin and eosin (H&E) staining, cell histochemistry technique, magnetic enzyme immunoassay of testosterone. We observed mainly the effect of different concentration of macrophage-conditioned media (MCM) on Leydig cells' basal testosterone production and morph...